This report presents an external evaluation of HMRC’s (His Majesty's Revenue and Customs) technical demonstrator for the Electronic Trade Documents Act (ETDA). Delivered in collaboration with the Cabinet Office and the International Chamber of Commerce UK’s Centre for Digital Trade and Innovation (C4DTI), the pilot assessed the operational and technical feasibility of digital trade documents for UK customs administration. The ETDA, enacted in September 2023, provides legal equivalence between electronic and paper trade documents. The pilot explored the benefits of digital documentation for both government and business, with a focus on improving customs compliance, reducing administrative costs, and enhancing trade efficiency. The evaluation applied a mixed-method approach. A Theory of Change (ToC) was employed to map intended pilot outcomes and pathways of impact. A meta-analysis of academic and institutional studies benchmarked potential economic effects. A quantitative case study used operational data from a participating customs service provider. Overall, the evidence traces a pathway from micro-level operational efficiencies at the firm level, such as reduced document processing times and lower per-declaration costs, through meso-level reductions in compliance burdens and transaction costs that benefit businesses, to macroeconomic effects on trade volumes, GDP, wages, and producer prices.